I'm pretty sure most guys in here pee sitting down
....using a gatorade bottle or similar.
I like to stand up and whip it out like WHAT!!!! but I guess that's why they don't let me fish in the bays anymore?
In all reality it just depends, if you can't easily move around on your yak go with the waders that have a zipper and use the bottle, but if your comfortable poping up to your knees, then that is by far the most liberating experience.